Lightning-conductor.



L. L. MAST.

LIGHTNING CONDUCTOR.

APPLICATION FILED DEO.16,1910

Patented Dec. 8, 1914.

lNVE/V TOR.

ATTORNEY.

- UNITED STATES PATENT OFFICE.

LOUISLJMAST, WEST MILTON, OHIO, ASSIGNOR T DELBERT H. MAST, OF

' WEST MILTON, OHIO.

LIGHTNING-CONDUCTOR.

To (ill whom it may comern: Bea known that I,LoU1s L. MAs'r, a c tizenfof the United States, residing at West Miltomdn the county of- Miami andState of Ohio, have invented certain Improvements' in LightningCond'uctors, of which thejfol'lowing' is a specification. My inventionrelates to means for constructi'ng and assembling lightning conductorsin such manner as to secure the maxi Iniuhj of efficiency consistentwith the material of which the conductor is made, and it relates moreparticularly to that class of conductors wherein a metal core is coveredby a sheathing of metal possessing the pro e a} of high electricalconductivity; n conductors of this class it is customary to make thecore'of iron and the sheathing of copper, the former for its strengthand rigidity and the latter for its conduot-i'ngfrop erties; An eminentauthority has sai that A given weight" of m'etaiis much more effectiveas a rapid carrier when in the form of a ribbon or tape, which statementeX-- presses-the consensus of opinion of many who are best qualified toknow, and it is upon this theory that the sheathed conductor is based.

Lightning conductors are commonly called lightning rods or rods andhereinafter I will generally refer to them by one of those terms. Thecore usually comprises four thin wedge shaped longitudinalribs,'ra'diating from a common center, and the sheathing is made toconform to the contour of this core. By this means a ribbon ofconsiderable width is reduced to a compact form, while retaining itsefiiciency as a rapid conductor.

In a Patent, No. 395,399, issued to me J anuary 1, 1889a sheathed rodwas shown and described, and one of the. objects of my present inventionis to improve on the manner of" interlocking the edges of the sheathingshown in my former invention.

Much of the benefit derived from the above described construction willbe lost, and has been lost heretofore in similarly constructed rods, byhaving imperfect joints between the several lengths of rod required inan installation. Therefore, the main objeot of. my present inventionisto construct and attach the couplings, or burs as they are frequentlycalled, to the rod in such manner and make them' of such material thatthe Specification of Letters Patent.

conductivity of the joints will equal the conductivity of the rod.

It is a well known fact that the eiiiciency of nearly all lightning rodinstallations is seriously impaired by imperfect electrical connectionat joints and branches. This is true of plain rods as well as coppersheathed ones, and my improvement in this respect resides in making thecouplings of a more ductile and less resilient metal than has been usedin the past, to make them of a metal having conductivity at least equaltothat of the rod itself, and secure them to the rod in such manner asto insure mechanical strength and a good and permanent electri calcontactbetween each coupling member and the rod it is joined to. In theaccompanying -,drawin Figure 1 IS a section through a section 0 rod.Fig. 2 is a similar section but showing a coupling at the distant end.Figs. 3, 4 and 5 show different way of making the coupling. Fig.

Patented Dec. 8, 1914.

A pplication fi led December 16,1910. Serial No. 597,682.

Similar. numerals indicate like parts throughout. .1; I

A core 20 of the usual ribbed section, is covered by the sheathing 21,which conforms to the contour of the core. Theftwo edges of thesheathing; one folded inwardly and the other outwardly, are hookedtogether,

forming the interlock 22,.and by placing the 'fold; z. 6., the portionof the sheathing which is actually bent when the edges are folded, ofthe inwardly turned edge at the junction of two ribs, the interlock isquite concealed. Besides appealing to the esthetic eye, this dispositionof the interlock has the advantage of bringing the exposed fold close.to the axis of the rod, where it will be sub jeoted to least strain whenthe rod is bent; and it has the further advantage of causing each memberof the interlock to be positiveiy held by the other member, therebypreventing dispiacement of either member without displacing the other.it is in the above described manner of disposingthe interiock that itssuperiority over the method I formerly empioyedresides. in the intervthe thread will be quite s'oft,-and-theporpreferable to'use lock shownin the patent referred to, there was practically nothing but friction tokeep one member attached to the other.

Fig. 3-shows my improved coupling before being attached to the ends ofthe rod. As will be seen, it is composed of members 24 and 25, male andfemale respectively, both of which are made of seamless drawn tubing,the former being contracted at one end and a thread cut on thecontracted end. The end of the'men1ber'25 abuts the shoulder 24 when thecoupling is screwed together. ends of the red, as in igs. 7, 10 and 11.To facilitate swaging, the tubing should be made. of a very ductilemetalf should also have electrical conductivity; at, .least equal tothat of the rod on whichfit isgh sed. Copper and aluminumare bothwell-adapted to the purpose, especially the former be cause of itssuperior conductivity, while the latter answers the purpose very Well onordinary galvanized iron rods. ,1;

As before stated, ductility is one of the requisites in the material ofwhich. the couplings are made, and to secure the desired ductility, thetubing, whichis hard when it" comesfrom the drawing dies, may beannealed. The member 24-shouldbe annealed before the end is contracted,which operation .will again harden the portion to be threaded, whileleaving the end to be swaged, soft. But if the member 25 is. annealed,

tion of'themember protruding beyond the rod after it is swaged on,.maybe easily injured in hahdl It 'may therefore be tl le'female withoutannealing, in which case, more care may be neces: sary in swag'ing it onthe rod.

Fig. 5 shows a coupling in which the male, 26, is contracted, whilethefemale, 27, is expanded. As expan'di ng metal hardens it as well ascontracting it does, this female may be annealed before it is expanded,and

as only the portion expanded :will be har-' dened, the portion to beswaged will remain j soft.

Fig. 4 shows athird coupling, in which a wire Spiral, 28, is screwed orsprung into sufficient to keep the wire in place and prevent it turningwhen the male, 30, is screwed the conpiings to the rods.

The couplin s are swaged on the hardened ends being threaded so thethread of the female 29, friction being Good electrical connectionsbetween a rod encircles the rod. The ends of the strap. 'are curved intosemi-cylindrical shape and the two together form a tube on which thethread 33 is out. At suitable intervals along each edge of the strap,tongues- 34- are formed; these tongues are bent so thatwhenthe strap ison the-rod they will point toward its center. The tongues are just theshape of the anglebetween adjacent ribs,

and when the strap is placed around the rod, its ends pressedtogetherand. the female member of a coupling screwed on, the strap isdrawn tightly around the-rod, pressing the edges of the tongues 34against the parts not touched'by the strap, thereby makin'g'a goodelectrical connection, as well as afvery rigid one mechanically. Thethree parts of the strap lying between the tongues can i be easily bentto permit of the; strap being placed on the rod. These straps areespecially useful for attaching po1nts'wher everthey are wanted. Forexample, a rod may be run along the ridge of a roof and atsuitableintervals these straps are laced on the rod and a point ofsuitable ength I It is customary to twist the screwed on. rod as showninFigs. 10 and 11, andwhen the strap is used on. a twisted rod itisobvious that a slight longitudinal movement on the rod will cause acorresponding r0; tary movement. Therefore, it is a very simple matterto clamp the strap at a place where itwill'hold the point perfectlyplumb, and it-is certain t o s tay plumb.

Minor changes may' be made in the various parts of my invention withoutdeparting from its nature or scope.

I claim-2. I I

1. A. coupling for lightning conductors,

comprising two pieces of tubing, one end I of each piece being hardenedwhile the re mainder of the piece remains soft, said one may bescrewed-into the other.

2 A lightning conductor having a core with a plurality ofsubstantiallylongitudinal ribs radiating from acommon center,

and a' sheathing which conforms .to' the .contour of the core; thesheathing being formed from a strip of sheet metal having itslongitudinal edges folded overupon it-' self, one inwardly and towardthe core, the other outwardly and away from the core, the latter havinga second bend in the same direction as the first, the second bend beingapproximately opposite the edge which was turned out by the first. bendand being placed at the junction of two ribs of the core, the inwardlyturned edge of the sheath ing being confined in the tube formed by thetwo outward bends of the other edge.

3. A clamp for connecting a branch to another lightning conductor,comprising a tapped member attached to the branch, and a band encirclingthe conductor, said band having semi-cylindrical threaded extensionswhich, when parailelly juxtaposed, form a screw on which said tappedmember at tached to the branch may be screwed, there by drawing saidextensions toward each other and causing the band to grip the conductor,said band having a succession of inwardly projecting tongues arrangedalong its edges, the contour of said tongues being complementary to andfor the purpose of engaging and forming electrical connection withportions of the conductor not touched by the body of the band.

i. A lightning conductor composed of longitudinal ribs radiating from acommon center, the ends of the ribs being bent laterally so as to form apronounced angle with the adjacent portion of the rib, whereby acoupling member secured to and conforming to the normal contour of therod wil be prevented from slipping ofl of the T0 i In a lightningconductor, the combination of a rod having longitudinal ribs radiatingfrom a common center, the ends of LOUIS L.-MAST.' 7

Witnesses:

D. H. MAST, F. K. FASSETT.

